Drylands represent 40% of the Earth's surface, produce 44% of the world’s food and are home to 80% of the world’s poor. Eighty per cent of Kenya comprises arid or semi-arid lands. Rainfall occurs in just one or two short, intense seasons. Because the land is so dry, when rain does fall, up to 85% of the water is simply lost as run-off. The rain also washes away fertile topsoil and seeds, negatively affecting agricultural production.

In 2002, Excellent Development UK and Excellent Development Kenya were established to upscale a model of soil and water conservation in Machakos County. The project involves revitalising an ancient method of rainwater harvesting through the introduction of sand dams and agroecological practices, which are spread through farmer-to-farmer field schools. The combination of soil conservation and agroecological practices, terracing and sand dams has increased soil moisture in the fields and enabled small-scale irrigation, significantly improving agricultural productivity.